Graphite-induced interface regulation in hard carbon for high-performance sodium-ion storage

In this work, we propose a graphite-induced interface strategy, in which pre-carbonized coconut shell carbon is wrapped with graphite paper and then carbonized. This process induces ordered rearrangement of carbon atoms on the hard carbon surface, forming ion transport channels composed of graphitic domains. These channels lower the kinetic barrier for Na+ entry into the internal closed pores, thereby converting inaccessible closed pores into accessible ones. The designed hard carbon achieves a high specific capacity of 359.64 mAh g−1 at 30 mA g−1, with a plateau contribution of 215.08 mAh g−1 and an excellent initial Coulombic efficiency of 91.21%.